it will be such a shock to the system that it has been called the fiscal cliff. our coverage starts on the white house lawn tonight with major garrett. major. >> reporter: scott, the saesident said for the first time, there is a two-step process to averting the fiscal cliff. republicans must act now to prevent a tax increase for households earning less than $250,000. do that now, president obama said, and he and congress can work out the details of spending cuts later. ( applause ) before a crowd of supporters, the white house invited from the mid-atlantic region, president obama put congressional republicans on notice. >> it's too important for washington to screw this up. now is the time for us to work on what we all agreed to, which is lets keep middle class taxes low. that's what our economy needs. that's what the american people deserve. gd if we get this part of it right, then a lot of the other issues surrounding deficit reduction in a fair and balanced, responsible way are going to be a whole lot easier. >> reporter: white house officials say mr. obama is